DE102018114351A1 - filter media - Google Patents

Abstract

The invention describes a filter medium (10), in particular for an air filter, in particular an interior air filter or for a fuel cell, comprising at least three active layers:
a catalytic active layer (12) comprising catalytic activated carbon particles (12a),
a second active layer (14) comprising impregnated or catalytic activated carbon particles (14a),
- A third active layer (16), the impregnated or catalytic activated carbon particles (16a), wherein at least one active layer impregnated activated carbon particles and the three active layers (12,14,16) are different from each other.
Furthermore, the invention discloses a filter media body comprising the filter medium; a filter element comprising the filter media body or the filter medium; an air filter comprising the filter element or the filter media body or the filter medium and a manufacturing method for producing the filter medium.

Description

Technical area

The invention relates to a filter medium according to the preamble of claim 1 and a filter media body according to claim 13, a filter element according to claim 14, an air filter according to claim 15 and a manufacturing method for a filter medium according to claim 16.

State of the art

Filter media, in particular for air filters, in particular for cabin air filters, serve a space, such as a passenger compartment of a motor vehicle, but z. As well as fuel cell cathode rooms to provide with purified air. Such filters should not only remove coarse contamination by particles, such as pollen or fine dust, but also remove odors, in particular by gaseous odors, or harmful or reactive gaseous substances. In particular, the removal of gases and odors is a challenge here, since the different gas and odorous substances by their different specific, especially chemical, properties require different adsorption. With the number of adsorption layers, however, the adsorption performance of the filter medium decreases. For example, there is a risk of inhomogeneity of the adsorption layers and, in general, the flow resistance of the filter medium, for example in an air filter, increases so that, for example, the energy consumption of an air-conditioning installation containing the air filter increases. Conventionally, filter media having multiple adsorption layers designed to be a compromise between the cleaning task and the power consumption is used. An air filter capable of freeing air from both particulate contaminants (solid and / or liquid) and gaseous contaminants is also referred to as a hybrid filter. Such hybrid filters are often specified by specification sheets, which usually consider the following gases: n-butane, toluene, sulfur dioxide, nitrogen oxides, and ozone. Such hybrid filters can also be specified, for example, according to ISO 11155 Part 2. Due to their age, these standards no longer depict the gas and odoriferous substances profiles, which are now particularly available in cities; In particular, odorous substances and harmful or reactive gaseous substances such. B. formaldehyde in the standard specifications is not or not sufficiently considered, so that the adsorption performance of conventional filters for specific odor profiles is often insufficient.

From the US 7,758,674 B2 a filter device for air filtering the air to be supplied to a fuel cell is known, wherein the filter device is to clean the air of both dirt particles and chemical contaminants. For this purpose, the filter device on a filter fleece on which the dirt particles are deposited, and a chemical filter area comprising a layer of activated carbon, comprising a surface coating with an acidic or basic material or an activated carbon impregnated with this material, and as adsorbent is used for adsorption of gaseous components in the air.

From the DE 10 2013 011 511 A1 a filter device, in particular for the air to be supplied to a fuel cell is known, comprising a carrier medium and activated carbon as adsorbent, wherein the activated carbon is immobilized by the addition of adhesive.

From the EP 1 468 718 A1 as well as from the DE 203 06 250 U1 an air filter unit having a plurality of filter elements is known, which contain activated carbon adsorbents as adsorption material, wherein the filter unit comprises at least a first filter element which comprises granular, in particular spherical activated carbon as adsorption material, and at least one second filter element which as adsorption a combination of granular, in particular spherical Includes activated carbon and activated carbon fibers. The filter unit is particularly suitable for use in (ventilation) ventilation systems, ventilation systems and air conditioning systems.

From the WO 2004/033069 A2 are filter media, in particular for water filtration in settling ponds based on activated carbon known comprising three superimposed layers, with an upper layer, a middle layer and a lower layer, wherein the middle layer to 80 to 95% of the dry weight of activated carbon, the difference to 100 % of organic and / or inorganic chemical fibers, the lower layer comprises from 45 to 100% of the dry weight organic chemical fibers with OH groups, optionally activated carbon and / or a material having a density less than 0.9, all or some of the OH R groups have reacted with a grafting agent RX, wherein R is a hydrophobic group which is liquid at at least 200 ° C and atmospheric pressure and wherein RX is suitable for forming a volatile leaving group HX in the reaction, the top layer comprises 5 to 25% the dry weight of activated carbon, the difference to 100% consists of organic and / or inorganic chemical fibers.

From the DE10 2012 005 380 A1 is a filter medium with biocidal effect for filtering air for an interior of a vehicle, comprising at least one filter layer and at least one biocide layer, the biocide layer comprising microcapsules formed from at least one polymer, wherein at least one biocide is stored on and / or in the microcapsules, and wherein the filter medium is one Carrier layer formed first filter layer, a formed as an activated carbon layer second filter layer, designed as a fine dust filter third filter layer, the biocide layer, formed as an activated carbon layer fourth filter layer and formed as a carrier fleece fifth filter layer.

From the WO 2012/100113 A1 For example, a filter medium comprising a first plurality of filter medium particles having a large substrate surface comprising at least one acidic saturant, a second plurality of filter medium particles having a large substrate surface comprising at least one metal oxide, and a third plurality of filter medium particles having a large size A substrate surface comprising an amine impregnating agent and wherein activated carbon for the adsorption bed of the filter is disclosed as well as a second plurality of filter medium particles comprising a phosphoric acid impregnated activated carbon and MgO / CaO based nanocrystalline material. Disclosed are several layers of impregnated activated carbon and nanocrystalline material embedded in an adsorbent bed. For optimum performance, a two-ply filter medium is disclosed having an upper layer comprising a homogeneous mixture of a MgO / CaO based nanocrystalline material and phosphoric acid impregnated Kureha activated carbon and a lower second layer of a single layer of Calgon URC.

From the DE 44 13 606 A1 is a combination filter, consisting of a particulate filter and an adsorption filter, in particular based on activated carbon, known, which is produced and impregnated by a wet-laid process in a single operation, wherein successively first the particulate filter layer and then the adsorption filter layer of a mixture of Adsorberteilchen and (enamel) fibers is produced by suction in a sieve mold with the dimensions corresponding to the end product and wherein the aqueous dispersion of fibers and adsorber also contains inorganic or organic substances for impregnation of the adsorber, in particular H ₃ PO ₄ .

From the WO 02/085426 A2 a breathing air filter is known, with an air-permeable shell and at least one filter layer, which is arranged in the shell and contains activated carbon.

From the US2002 / 0088346 A1 is a sheet-form filter mass for an air-enclosed space filter, in particular a motor vehicle interior, comprising standard type materials for molding filter masses and carbon elements activated for the adsorption of gaseous substances.

From the GB 2 296 666 A For example, there is known a lifesaving apparatus comprising a motor for driving a disc, a connecting rod whose upper end is disposed with the disc and whose lower end is disposed with the upper end of a compressible bellows, the bellows being inflated and compressed by the connecting rod to receive outside air to suck a filter bottle, wherein the filter bottle has net filter layers and wherein a plurality of activated carbon filter layers are arranged one above the other in the filter bottle.

From the DE 7 110 985 U is a filter for gas streams, in particular for gas streams containing radioactive or chemical particles, eg. As air, known having two or more layers of honeycomb material are slightly offset from each other so that the cells in one layer are not in alignment with the cells of another "adjacent position that the cells contain granules of activated carbon and that the edges of the layers are covered with layers of foamed plastic which are sealed to a surrounding molded frame.

From the DE 10 2012 007 503 A1 an adsorptive filter medium is known, in particular for the purification of gases and / or gas mixtures, preferably air, and / or in particular for the removal of chemical and / or biological poisons and / or pollutants from gases and / or gas mixtures, preferably air, wherein the filter medium a A plurality of a first filter element with a first adsorption material, in particular in the form of adsorbent particles, and a plurality of a second filter element different from the first filter element with a second adsorption material, in particular in the form of adsorbent particles, wherein the first filter element and the second filter element from each other different pressure losses and / or have different (through) flow resistances and wherein the first adsorption material and / or the second adsorption material, independently of one another, can be selected from the group of activated carbon, in particular granular activated carbon, preferably kug eliform activated carbon and / or in particular shaped and / or extruded activated carbon and / or pulverulent activated carbon and wherein the first adsorption material and / or the second adsorption material, independently of one another, from particular particulate activated carbon, in particular from granular, preferably spherical activated carbon, may be formed.

From the WO 2010/127634 A1 For example, a multilayer filter is known having an upper layer and a lower layer comprising a plurality of layers of a substrate medium and a plurality of layers of nanofibers, the upper layer and the lower layer each having a layer of the nanofibers and between the upper and lower layers at least one unit comprising two layers of nanofibers between two substrate medium layers, and wherein a substrate medium layer may comprise activated carbon fibers.

From the DE 10 2015 205 551 A1 is a multilayer filter material for a cabin air filter element of an air conditioning system of a vehicle known for adsorbing particular odors, wherein the multilayer filter material comprises an active layer comprising unimpregnated activated carbon particles, an impregnating layer having impregnated activated carbon particles, and an ion exchange layer having ion exchanger particles.

From the DE 10 2005 016 677 A1 a filter element with a multilayer filter material is known, in which an active material layer arranged on the upstream side is provided with activated carbon fibers, to which an adsorbent layer with granular adsorbents adjoins downstream. At the downstream side, a further active layer with activated carbon fibers can connect to this adsorber layer. The adsorbents used here can comprise activated carbon, zeolites, cyclodextrins, silicates, ion exchangers and aluminosilicates.

From the DE 10 2012 007 503 A1 a further adsorptive filter medium is known in which a plurality of first filter layers are provided with a first adsorbent and a plurality of second filter layers having a second adsorbent different from the first filter layers, which alternate with each other and have different flow resistances or pressure losses.

From the DE 10 2009 021 020 A1 Another adsorptive filter material is known which contains an exchange resin loaded with metal cations.

The invention has for its object to provide a filter medium that a high and balanced adsorption for a wide range of gas, and thus for various properties comprehensive gas and odor profiles, in particular for n-butane, VOCs, NOx, SO ₂ , H ₂ S. , NH ₃ and CH ₂ O comprising gas and odoriferous profiles.

Disclosure of the invention

This object is achieved by a filter medium having the features of claim 1, a filter media body having the features of claim 13, a filter element according to claim 14 and an air filter with the features of claim 15. The dependent claims indicate advantageous and expedient developments.

The filter medium according to the invention, in particular for an air filter, in particular an interior air filter or for a fuel cell, comprises a catalytic active layer comprising catalytic activated carbon particles, in particular consisting of a second active layer comprising impregnated or catalytic activated carbon particles, in particular consisting of a third active layer, the impregnated or catalytic activated carbon particles, in particular consists thereof, wherein at least one active layer impregnated activated carbon particles, wherein the three active layers are different from each other.

As the activated carbon active carbon is suitable in which by an activation method, the electronic structure of the carbon of the surface is changed. In one embodiment, 1 g of catalytic activated carbon at a temperature of 23 ° C and standard pressure in a mixture of 80 ml of water and 30 ml 30 wt .-% H ₂ O ₂ solution is added, followed by a temperature increase of> 23 ° C after 5 min and> 33 ° C after 10 min. A proof of the catalytic property of the activated carbon can thus be so lead.

As impregnated activated carbon is an activated carbon suitable having an applied to the carbon impregnation. The gas and odorants to be removed are chemically bound by the impregnation applied to the carbon or converted by this into an adsorbable form of the next active layer. In other words, the impregnations applied to the activated carbon have a chemisorptive effect with the respective gas or odor substance. The impregnated active layer thus has additional chemisorption properties that enhance adsorption or adapt it to a predetermined compound profile. The impregnation can be applied to an activated carbon or to a catalytic activated carbon in the sense of the invention. Suitable impregnations are, for example, potassium carbonate for the targeted removal of acid gases (pH <7 under standard conditions and measured in aqueous solution), hydrogen sulfide, sulfur dioxide or nitrogen oxides, phosphoric acid (H ₃ PO ₄ ) and / or sulfuric acid (H ₂ SO ₄ ) for targeted removal of alkaline gases (pH> 7 at standard conditions and measured in aqueous solution), ammonia and amines, and / or potassium iodide for the targeted removal of hydrogen sulfide, and / or sodium hydroxide (NaOH) for the targeted removal of acidic gases and hydrogen sulfide, and / or sulfur and / or silver.

In particular, the impregnated active layer may comprise a multi-impregnated activated carbon which has been treated with at least two of the abovementioned substances. Preference is given to an impregnated activated carbon which has been impregnated with phosphoric acid and ethylene urea. In addition, it is possible that the impregnated active layer has a mixture of at least two activated carbon particles impregnated with different substances.

In a preferred embodiment, the filter medium comprises an active layer comprising catalytic activated carbon particles, a second active layer comprising impregnated activated carbon particles, and a third active layer comprising impregnated or catalytic activated carbon particles.

In a particularly preferred embodiment, the filter medium comprises an active layer comprising catalytic activated carbon particles, a second active layer comprising impregnated activated carbon particles, and a third active layer comprising impregnated activated carbon particles.

The order of the active layers is freely selectable according to the invention and can be selected adapted to a specific gas and odor profile. For example, the order of the active layers may be first selected as the outer active layer, the second active layer comprising impregnated activated carbon particles, interposed therebetween as the intermediate active layer, a catalytic active layer comprising activated charcoal carbon particles, and finally the third outer active layer comprising impregnated activated carbon particles , The first, outer active layer is preferably a catalytic active layer in the sequence. This has the advantage that the second active layer can be easily adapted to the moisture content and the still acidic environment (pH <7) of the gas stream.

It is also conceivable for the filter medium to comprise as a sequence a first, outer active layer comprising catalytic activated carbon particles, a second, middle active layer comprising catalytic activated carbon particles and having the third, outer active layer, impregnated activated carbon particles.

The filter medium according to the invention can be adapted so advantageous to the specific requirements of a particular gas and odor profile. In particular, a gas and odor substance profile composed, for example, of an acidic (pH <7) and / or hydrophilic gas and odor substances and basic (pH> 7) and / or organic, in particular hydrophobic, gas and odor substances, in particular comprising Butane, VOCs, NOx, SO ₂ , H ₂ S, NH ₃ and CH ₂ O, are filtered with good adsorption performance.

In one embodiment of the filter medium, the catalytic active layer comprises activated carbon catalytic particles for removing acidic (pH <7 under standard conditions and measured in aqueous solution) and / or hydrophilic gases. This has the advantage that both hydrophilic and acidic (pH <7) gases and water in the gas stream of basic and / or organic, in particular hydrophobic, gas and odorous substances, in particular harmful or reactive gaseous substances, are separated in a simple manner.

In one embodiment of the filter medium, the catalytic active layer catalytically has activated carbon particles with a mass density of 50 to 300 g / m ² , in particular 150 to 300 g / m ² .

In one embodiment of the filter medium, the catalytic activated carbon particles are bound by the addition of adhesive, in particular crosslinked. This bond, in particular crosslinking, is advantageously achieved by the addition of adhesive, the adhesive threads of which adhere to the surface of the activated carbon particles and connect various activated carbon particles with one another, but without impairing the adsorption performance of the activated carbon. Suitable adhesives include, for example, reactive melt flow adhesives, e.g. B. based on polyurethane or silane. Also possible is a thermoplastic adhesive, the z. B. is prepared based on polyolefins.

In one embodiment of the filter medium, the second active layer comprises impregnated activated carbon particles for removing ammonia.

In a further embodiment, the second active layer comprises phosphoric acid-impregnated activated carbon particles. The impregnation with phosphoric acid (H ₃ PO ₄ ) has the advantage that ammonia (NH ₃ ) by chemisorption and thus in contrast to physisorption more strongly bound by chemical bonds to the adsorbent (substrate) and thus adsorbed particularly safe. In further embodiments, the impregnation consists of 2 to 15 wt .-%, in particular 3.5 to 15 wt .-%, in particular 2 to 6 wt .-% phosphoric acid.

In a further embodiment, the second active layer has impregnated activated carbon particles with a mass coverage of 50 to 300 g / m ² , in particular 50 to 150 g / m ² .

In another embodiment, the first outer active layer in the order is a catalytic active layer comprising catalytic activated carbon particles. By combining the choice of order and by an additional adjustment the mass occupancy can be achieved an additional favorable coal-to-adhesive ratio.

The active layers in embodiments may be directly adjacent to each other.

In further embodiments, the impregnated activated carbon particles are bound by the addition of adhesive, in particular crosslinked. This bonding, in particular crosslinking is advantageously achieved by the addition of adhesive whose adhesive threads adhere to the surface of the activated carbon particles and connect different activated carbon particles with each other, but without impairing the adsorption performance of the activated carbon. Suitable adhesives include, for example, reactive melt flow adhesives, e.g. B. based on polyurethane or silane. Also possible is a thermoplastic adhesive, the z. B. is prepared based on polyolefins.

In another embodiment, the adhesive is a reactive melt flow adhesive.

In a further embodiment, the third active layer comprises impregnated activated carbon particles for removing ammonia and formaldehyde. This has the advantage that in particular residues of ammonia are removed with particular care. In addition, such a layer is additionally designed simply for the reliable adsorption of formaldehyde.

In a further embodiment, the third active layer comprises impregnated activated carbon particles with ethylene urea and phosphoric acid. This has the advantage that both the ammonia and, for example, formaldehyde are chemically bound to the adsorption substrate by chemisorption. In further embodiments, the impregnation consists of 2 to 15 wt .-%, in particular 3.5 to 15 wt .-%, in particular 2 to 6 wt .-% phosphoric acid and 10 to 20 wt% ethylene urea.

In a further embodiment, the third active layer has impregnated activated carbon particles with a mass coverage of 50 to 300 g / m ² , in particular from 50 to 150 g / m ² . This has the additional advantage that the small molecular size formaldehyde and also the ammonia are adsorbed particularly advantageous.

In a further embodiment, the impregnated activated carbon particles are bound by the addition of adhesive, in particular crosslinked. This bonding, in particular crosslinking is advantageously achieved by the addition of adhesive whose adhesive threads adhere to the surface of the activated carbon particles and connect different activated carbon particles with each other, but without impairing the adsorption performance of the activated carbon. Suitable adhesives include, for example, reactive melt flow adhesives, e.g. B. based on polyurethane or silane. Also possible is a thermoplastic adhesive, the z. B. is prepared based on polyolefins.

In another embodiment, the adhesive is a reactive melt flow adhesive.

In a further embodiment, the filter medium has at least one carrier layer. The carrier layer may be formed, for example, as a textile carrier layer, in particular as a nonwoven. The carrier layer may in this case be the carrier of the activated carbon particles or at least adjacent to the active layer. The carrier layer is embodied, for example, as a carrier layer or layer, which optionally takes over a mechanical filtration of particulate impurities of the gas stream to be cleaned. In this case, the carrier layer forms, for example, a carrier or filter fleece, on which dirt particles can be deposited. The fleece consists z. Example of polyester, polypropylene, polyamide, polyacrylonitrile or polycarbonate.

In one embodiment, the activated carbon forms an active layer immediately adjacent to the carrier layer, which is preferably connected to the carrier layer via the adhesive. In this case, both sticking of the active layer to the carrier layer into consideration as well as the bonding on not yet set adhesive threads, which are applied to the activated carbon particles. The carrier layer thus limits the active layer at least on one side and is at the same time connected to the active layer. This embodiment allows the formation of open carrier-layer activated carbon layers with fixed activated carbon particles. Such carrier layer-activated carbon layer layers comprise at least one carrier layer and an activated carbon layer, and can be stacked easily, wherein the flow direction is preferably in the stacking direction, that is orthogonal to the plane of the layers.

In a further embodiment, at least two carrier layers are provided, wherein the filter medium is preferably formed without additional filtration layer. In this embodiment, the at least three active layers within an upper and a lower carrier layer are directly adjacent to each other.

According to an alternative embodiment, at least one active layer may be delimited at its two side surfaces by a respective carrier layer. Conveniently, the active layer is additionally glued to both carrier layers.

In a further embodiment, the filter medium has a filtration layer, in particular a particle filter layer. The filtration layer is in particular formed as a textile particle filter layer, in particular as a nonwoven.

According to a further expedient embodiment, at least one active layer can be sealed on its longitudinal and / or broad sides, so that, if appropriate, an all-round delimitation of the activated carbon layer can be realized together with the carrier layers present on the side surfaces. The sealing on the longitudinal and / or broad sides increases the stability and improves the security against delamination and displacements in the respective active layer.

According to a further expedient embodiment, at least one active layer can be provided with a seal at its end faces, that is to say the broad sides and the longitudinal sides. Immediately superimposed active layers are advantageously not glued together, but the bonding is done only on the immediately adjacent carrier layer.

Suitable types of activated carbon are, for example, activated carbons based on various raw materials, such as coconut, hard coal, charcoal or synthetic starting materials, having different degrees of activation, different catalytic properties and different impregnations. As a result, an additional advantageous adaptation to the target gas spectrum is possible. Preferred raw materials here are coconut, hard coal and charcoal, coconut activated carbon being particularly preferred here.

The object is also achieved by a filter media body comprising a filter medium according to the invention and at least one sideband.

In one embodiment, the filter media body is designed as a wound body, layered as a flat filter or folded as a filter bellows.

The object is also achieved by a filter element comprising a filter media body according to the invention or a filter medium according to the invention, a frame, holding elements and at least one seal. In one embodiment, the filter element is an air filter element. In a further embodiment, the filter element is an interior air filter element.

The object is also achieved by an air filter comprising a filter element according to the invention or a filter media body according to the invention or a filter medium according to the invention. In one embodiment, the air filter is an indoor air filter.

The object is also achieved by a fuel cell comprising an air filter according to the invention or a filter element according to the invention or a filter media body according to the invention or a filter medium according to the invention.

The object is also achieved by an air conditioning system comprising an air filter according to the invention or a filter element according to the invention or a filter media body according to the invention or a filter medium according to the invention.

The object is also achieved by a use of the filter medium according to the invention in air-conditioning systems, cabin filters, filter elements, air filters, in particular room air filters, ventilation systems, ventilation systems, fuel cells, in particular fuel cell air filters, in particular fuel cell cathode air filters.

A process for producing a filter medium according to the invention comprising the steps of applying a first, catalytic active layer comprising catalytic activated carbon particles, in particular consists, on a support layer, applying a second active layer, the impregnated or catalytic activated carbon particles, in particular consists thereof, on the first active layer , Applying a third active layer, the impregnated or catalytic activated carbon particles, in particular consists thereof, on the second active layer, wherein the order of the first, second and third active layer interchangeable selectable and wherein additionally a filtration layer or a further carrier layer on the last applied activated carbon layer is applied.

In a preferred embodiment, the at least one active layer has impregnated activated carbon particles.

In a preferred embodiment of the method according to the invention, a catalytic active layer comprising catalytic activated carbon particles is applied to a carrier layer, subsequently an active layer comprising impregnated activated carbon particles is applied, and subsequently an active layer is applied which comprises impregnated or catalytic activated carbon particles.

In a further embodiment of the method, an adhesive is applied in each case before the application of the respective active layer.

In further embodiments of the method, at least one further carrier layer applied, in particular, for example, a further carrier layer is applied to the third active layer.

In further embodiments of the method, a filtration layer is additionally applied.

The invention additionally comprises a filter medium produced by the method according to the invention.

list of figures

• 1 eine stark vereinfachte, Schnittansicht eines Filtermediums gemäß einer Ausführungsform.

It shows, in each case schematically:

• 1 a highly simplified, sectional view of a filter medium according to an embodiment.

Embodiment (s) of the invention

In 1 is a filter medium 10 illustrated, in particular for an air filter, in particular an interior air filter or for a fuel cell wherein the filter medium is an outer catalytic active layer 12 , the catalytic activated carbon particles 12a has a second, middle active layer 14 , the impregnated activated carbon particles 14a and a third, outer active layer 16 , the impregnated or catalytic activated carbon particles 16a wherein at least one active layer, for example the third active layer 16 impregnated activated carbon particles 16a having. The catalytic activated carbon particles 12a the catalytic, in the 1 outer active layer 12 of the filter medium 10 can, as in 1 shown schematically, also by the addition of adhesive 18 bound, in particular crosslinked be. The adhesive 18 may advantageously be a reactive melt flow adhesive, for example based on polyurethane. The adhesive 18 In addition, it may additionally be advantageous to use a filtration layer 20 , in particular a particle filter layer 20 , with the catalytic active layer 12 connect. The catalytic activated carbon particles 12a the catalytic active layer 12 may have a mass density of 50 to 300 g / m ² , in particular 150 to 300 g / m ² . The catalytic active layer 12 advantageously has catalytic activated carbon particles 12a for removal of acidic (pH <7) and / or hydrophilic gases and so removes hydrophilic gases and also adsorbs a portion of the water in the gas stream. As a result, the gas stream is dried in a simple manner before passing through an active layer designed for basic and / or organic, in particular hydrophobic, gas and odor substances, in particular harmful or reactive gaseous substances, for example the second active layer 14 , whereby the adsorption performance for basic and / or organic, in particular hydrophobic, gas and odor substances harmful or reactive gaseous substances, is additionally optimized.

The impregnated activated carbon particles 14 a of the second active layer 14 of the filter medium 10 can like in 1 shown schematically also by the addition of adhesive 18 bound, in particular crosslinked be. The adhesive 18 may advantageously be a reactive melt flow adhesive, for example based on polyurethane. Advantageously, the second active layer 14 impregnated activated carbon particles 14a for the removal of ammonia, in particular phosphoric acid impregnated activated carbon particles 14a , The phosphoric acid impregnation causes a chemisorption of ammonia from the gas stream to be purified. For example, the impregnation off 2 to 15 Wt .-%, in particular 3.5 to 15 Wt .-%, in particular 2 to 6 Wt .-% phosphoric acid.

The chemisorption in this case allows a stronger compared to the physisorption chemical bonds to the adsorbent, whereby the ammonia is bound particularly advantageous. Particularly advantageous, the impregnated activated carbon particles 14 a of the second active layer 14 a mass density of 50 to 300 g / m ² , in particular 50 to 150 g / m ² , have. The mass assignment can be easily adapted to the moisture content of the active layer and the environment of the gas stream, thereby a smaller amount of adhesive is required to the impregnated activated carbon particles 14a to bind, in particular to network. By adapting the mass allocation, a favorable coal-to-adhesive ratio is also achieved in a simple manner. The second active layer 14 is particularly advantageous as a middle layer between the catalytic outer active layer 12 and the third, outer active layer 16 arranged.

The impregnated activated carbon particles 16a the second active layer 16 of the filter medium 10 can like in 1 also shown schematically by the addition of adhesive 18 bound, in particular crosslinked be. The adhesive 18 may advantageously be a reactive melt flow adhesive, for example based on polyurethane. The adhesive 18 In addition, it can additionally advantageously have a particle filter layer 20 with the first active layer 12 connect. The third active layer 16 can in particular impregnated activated carbon particles 16a for removing ammonia and formaldehyde. For example, the third active layer 16 activated carbon particles impregnated with ethyleneurea and phosphoric acid 16a exhibit. The impregnated activated carbon particles 16a the third active layer 16 may have a mass density of 50 to 300 g / m2, having in particular 50 to 150 g / m ^2. For example, the impregnation of 2 to 15 wt .-%, in particular 3.5 to 15 wt .-%, in particular 2 to 6 wt .-% phosphoric acid and 10 to 20 wt% ethylene urea consist.

The filter medium 10 Can also be a carrier layer 22 , in particular a textile carrier layer 22 , in particular a carrier layer designed as a nonwoven 22 , exhibit.

The filter medium 10 can also have a filtration layer 20 have, in particular as a textile particle filter layer 20 may be formed, in particular may be formed as a nonwoven.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7758674 B2 [0003]
• DE 102013011511 A1 [0004]
• EP 1468718 A1 [0005]
• DE 20306250 U1 [0005]
• WO 2004/033069 A2 [0006]
• DE 102012005380 A1 [0007]
• WO 2012/100113 A1 [0008]
• DE 4413606 A1 [0009]
• WO 02/085426 A2 [0010]
• US 2002/0088346 A1 [0011]
• GB 2296666A [0012]
• DE 7110985 U [0013]
• DE 102012007503 A1 [0014, 0018]
• WO 2010/127634 A1 [0015]
• DE 102015205551 A1 [0016]
• DE 102005016677 A1 [0017]
• DE 102009021020 A1 [0019]

Claims (20)

Filter medium (10), in particular for an air filter, in particular an interior air filter or for a fuel cell, comprising at least three active layers: a catalytic active layer (12) comprising catalytic activated carbon particles (12a), a second active layer (14) comprising impregnated or catalytic activated carbon particles (14a), - A third active layer (16), the impregnated or catalytic activated carbon particles (16a), wherein at least one active layer impregnated activated carbon particles and wherein the three active layers (12,14,16) are different from each other. Filter medium (10) according to Claim 1 characterized in that the filter medium (10) comprises an active layer (12) comprising activated charcoal activated carbon particles (12a), a second active layer (14) comprising impregnated activated carbon particles (14a), and a third active layer (16) impregnated or comprising catalytic activated carbon particles. Filter medium (10) according to Claim 1 or 2 characterized in that the catalytic active layer (12) comprises activated carbon catalytic particles (12a) for removing acidic (pH <7) and / or hydrophilic gases. Filter medium (10) according to Claim 1 to 3 , characterized in that the catalytic activated carbon particles (12a) by the addition of adhesive (18) bound, in particular crosslinked, are. Filter medium (10) according to one of the preceding claims, characterized in that the second active layer (14) comprises impregnated activated carbon particles (14a) for removing ammonia. Filter medium (10) according to one of the preceding claims, characterized in that the second active layer (14) comprises phosphoric acid impregnated activated carbon particles (14a). Filter medium (10) according to one of the preceding claims, characterized in that the impregnated activated carbon particles (14a) by the addition of adhesive (18) bound, in particular crosslinked, are. Filter medium (10) according to one of the preceding claims, characterized in that the third active layer (16) impregnated activated carbon particles (16a) for removing ammonia and formaldehyde. Filter medium (10) according to one of the preceding claims, characterized in that the third active layer (16) with ethylene urea and phosphoric acid impregnated activated carbon particles (16a). Filter medium (10) according to one of the preceding claims, characterized in that the impregnated activated carbon particles (16a) by the addition of adhesive (18) bound, in particular crosslinked, are. Filter medium (10) according to one of the preceding claims, characterized in that the filter medium (10) has at least one carrier layer (22). Filter medium (10) according to one of the preceding claims, characterized in that the filter medium (10) has a filtration layer (20). Filter media body comprising a filter medium (10) according to one of Claims 1 to 12 , and at least one sideband and / or at least one headband. Filter element comprising a filter media body according to Claim 13 , or a filter medium (10) according to one of Claims 1 to 12 , a frame, at least one retaining element and / or at least one seal. Air filter comprising a filter element according to Claim 14 , a filter media body according to Claim 13 or a filter medium (10) according to one of Claims 1 to 12 and a housing. Process for producing a filter medium according to one of the Claims 1 to 12 comprising the steps of: - depositing a first catalytic active layer (12) comprising activated charcoal catalytic particles (12a) on a support layer, - applying a second active layer (14) comprising impregnated or catalytic activated carbon particles (14a) to the first active layer - applying a third active layer (16), the impregnated or catalytic activated carbon particles (16a), on the second active layer, wherein the order of the first, second and third active layer interchangeable selectable and wherein additionally a filtration layer or a further carrier layer on the last applied activated carbon layer is applied. Method according to Claim 16 , characterized in that at least one active layer comprises impregnated activated carbon particles. Method according to Claim 16 or 17 , characterized in that on a carrier layer - a catalytic active layer (12) comprising catalytic activated carbon particles (12a) is applied, - subsequently an active layer (14) comprising impregnated activated carbon particles (14a) is applied, and subsequently an active layer (16) impregnated or catalytic Activated carbon particles (16a) is applied. Method according to Claim 16 to 18 , characterized in that in each case before the application of the respective active layer (12), an adhesive (18) is applied in at least one further step. Method according to Claim 16 to 19 , characterized in that in a further step at least one further carrier layer (22) is applied.

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